The drinking water for more than 28 million people was screened for a diverse group of pharmaceuticals, potential endocrine disrupting compounds (EDCs), and other unregulated organic contaminants. Source water, finished drinking water, and distribution system (tap) water from 19 U.S. water utilities was analyzed for 51 compounds between 2006 and 2007. The 11 most frequently detected compounds were atenolol, atrazine, carbamazepine, estrone, gemfibrozil, meprobamate, naproxen, phenytoin, sulfamethoxazole, TCEP, and trimethoprim. Median concentrations of these compounds were less than 10 ng/L, except for sulfamethoxazole in source water (12 ng/L), TCEP in source water (120 ng/L), and atrazine in source, finished, and distribution system water (32, 49, and 49 ng/L). Atrazine was detected in source waters far removed from agricultural application where wastewater was the only known source of organic contaminants. The occurrence of compounds in finished drinking water was controlled by the type of chemical oxidation (ozone or chlorine) used at each plant. At one drinking water treatment plant, summed monthly concentrations of the detected analytes in source and finished water are reported. Atenolol, atrazine, DEET, estrone, meprobamate, and trimethoprim can serve as indicator compounds representing potential contamination from other pharmaceuticals and EDCs and can gauge the efficacy of treatment processes.

Cyanobacteria are ubiquitous microorganisms considered as important contributors to the formation of Earth's atmosphere and nitrogen fixation. However, they are also frequently associated with toxic blooms. Indeed, the wide range of hepatotoxins, neurotoxins and dermatotoxins synthesized by these bacteria is a growing environmental and public health concern. This paper provides a state of the art on the occurrence and management of harmful cyanobacterial blooms in surface and drinking water, including economic impacts and research needs. Cyanobacterial blooms usually occur according to a combination of environmental factors e.g., nutrient concentration, water temperature, light intensity, salinity, water movement, stagnation and residence time, as well as several other variables. These environmental variables, in turn, have promoted the evolution and biosynthesis of strain-specific, gene-controlled metabolites (cyanotoxins) that are often harmful to aquatic and terrestrial life, including humans. Cyanotoxins are primarily produced intracellularly during the exponential growth phase. Release of toxins into water can occur during cell death or senescence but can also be due to evolutionary-derived or environmentally-mediated circumstances such as allelopathy or relatively sudden nutrient limitation. Consequently, when cyanobacterial blooms occur in drinking water resources, treatment has to remove both cyanobacteria (avoiding cell lysis and subsequent toxin release) and aqueous cyanotoxins previously released. Cells are usually removed with limited lysis by physical processes such as clarification or membrane filtration. However, aqueous toxins are usually removed by both physical retention, through adsorption on activated carbon or reverse osmosis, and chemical oxidation, through ozonation or chlorination. While the efficient oxidation of the more common cyanotoxins (microcystin, cylindrospermopsin, anatoxin and saxitoxin) has been extensively reported, the chemical and toxicological characterization of their by-products requires further investigation. In addition, future research should also investigate the removal of poorly considered cyanotoxins (β-methylamino-alanine, lyngbyatoxin or aplysiatoxin) as well as the economic impact of blooms.

For over 70 years, scientists have reported that certain synthetic and natural compounds could mimic natural hormones in the endocrine systems of animals. These substances are now collectively known as endocrine-disrupting compounds (EDCs), and have been linked to a variety of adverse effects in both humans and wildlife. More recently, pharmaceuticals and personal care products (PPCPs) have been discovered in various surface and ground waters, some of which have been linked to ecological impacts at trace concentrations. The majority of EDCs and PPCPs are more polar than traditional contaminants and several have acidic or basic functional groups. These properties, coupled with occurrence at trace levels (i.e., <1 μg/L), create unique challenges for both removal processes and analytical detection. Reports of EDCs and PPCPs in water have raised substantial concern among the public and regulatory agencies; however, very little is known about the fate of these compounds during drinking and wastewater treatment. Numerous studies have shown that conventional drinking and wastewater treatment plants can not completely remove many EDCs and PPCPs. Oxidation with chlorine and ozone can result in transformation of some compounds with reactive functional groups under the conditions employed in water and wastewater treatment plants. Advanced treatment technologies, such as activated carbon and reverse osmosis, appear viable for the removal of many trace contaminants including EDCs and PPCPs. Future research needs include more detailed fate and transport data, standardized analytical methodology, predictive models, removal kinetics, and determination of the toxicological relevance of trace levels of EDCs and PPCPs in water.